Questions regarding password-based authentication and password management

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How to set default password algorithm to sha512 on Linux?

on AIX, it would be a simple: chsec -f /etc/security/login.cfg -s usw -a pwd_algorithm=ssha512 Question: But how can we set the default password algorithm to sha512? UPDATE: I think pwd_algorithm ...
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2answers
2k views

How to disable the try again password in ssh command

I want the ssh command to only allow one chance in typing the password, if the password was wrong at the first time the ssh will return Permission denied (publickey......). Is there a flag that ...
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1answer
2k views

Not able to set password in ArchLinux

I logged in as root and created a new account: # useradd -d /home/onie -m onie # su onie Now I try to set the password for onie myself using the passwd command, but it's asking for my current ...
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1answer
1k views

What triggers this screen prompt “Screen used by <username> on host01.”?

Every now and then some key combination clears my working (Gnu) screen and brings up this message: Screen used by <username> on host01 Password: What key combination causes this and what does ...
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4answers
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Force Firefox to remember passwords on particular sites

Usually, when I log into a website with username and password, Firefox asks whether it should remember the login details. When I click yes, next time I visit the website, the username and password ...
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2answers
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How to check for empty passwords?

Looking at all the ssh-login attempts by script-kiddies I assume that there are messed up systems connected to the internet that have password-less accounts set up. But how to check a Linux/Unix ...
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2answers
494 views

Why is 8 numbers considered a “strong” password?

Just curious as to why 8 numbers are accepted as a password in linux (CentOS if it matters) and not 8 characters on a non-dictionary word. It's 10 vs 26 per digit after all. (52 counting CaSe ...
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1answer
237 views

Is it safe for my ssh user to be given passwordless sudo for `apt-get update` and `apt-get upgrade`?

I have an SSH standard user account on my personal server, and it has sudo access (via its password). I ssh in using a public key, so I don't have to type in the account password to log in. Is it ...
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2answers
5k views

Graphically ask for password in a bash script and retain default sudo timeout setting

The sudo -A (SUDO_ASKPASS) option apparently causes sudo to lose the timeout (e.g., timestamp_timeout) setting. I want to use the sudo -A option but I want to retain the default timeout (e.g., 15 ...
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1answer
47k views

How to lock users after 5 unsuccessful login tries?

How to lock users after 5 unsuccessful login tries? I gathered a few distributions/versions to how to do it, but I can't test it. RHEL4: by adding the: auth required ...
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1answer
440 views

Automated ssh login with passphrase?

Logging onto a machine over ssh typically requires a password to be entered before access is granted. Alternatively, a key/certificate (without a passphrase) can be installed onto the remote machine ...
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2answers
514 views

Is it possible to change passwords temporarily?

I have a Linux system with several users. I don't know their passwords, nor do I want to know them. I have to do a batch copy of some of their directories over SSH, with their account and password. ...
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2answers
3k views

Why does pam_mount ask for password?

I used the pam-auth-update tool in order to enable some pam configuration profiles: PAM configuration PAM profiles to enable: [*] encfs encrypted home directories [*] Unix ...
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3answers
1k views

securely automating a script which requires a key to do its task

I have a script that downloads bank transactions to store in a database. To get these transactions requires a password for each account. The database is encrypted and requires a key to access it. All ...
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1answer
4k views

Changing password in multiple boxes using script

I'm working in a environment which has around 400 AIX boxes. I don't have root access and I'm a normal user. The environment has no LDAP kind of centralized mechanism for authentication so the ...
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1answer
4k views

Preventing `passwd` for asking for the local password

I have setup the sever to only use LDAP for authentication by using authconfig-tui. Everything works well but, when I run passwd, I get two prompts for a password: [beamin@rhel6-test-server1 ~]$ ...
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4answers
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automatic passwordless ssh at login/restart

I want to have passwordless ssh to persist even after after I restart or logoff and then login. Somehow I have to run ssh-agent and use command ssh-add at login. In a tutorial I read that I should add ...
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1answer
4k views

Samba passwords expiring in x days - how do we fix them to not expire

We use OpenLDAP and Samba v3. Recently some Samba-defined users (no accounts on the shared linux server) started being listed in logwatch as having their passwords come up to "will expire"...I ...
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2answers
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Can KWallet manage my ssh passwords?

I need a way to store some SSH passwords. Note that these are login passwords which I need to pass to ssh; key authentication is unfortunately not an option. I'd like to be able to have KWallet fill ...
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3answers
857 views

Any disk encryption that locks itself for some time after a number of failed attempts?

Is there any way to have your disk/partition/file encrypted (in Linux or as a hardware encryption; no Windows here) in such way that it locks itself for say 10 minutes after say 3 failed unlock ...
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2answers
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Sudo Su automated login

I want to automate the login process with sudo su. I have seen lot of questions on these, but none of them are working for me. Automate login with sudo and su Here's my what I tried so far echo ...
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3answers
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SCP command with selected file and directories for download ask's for password for each new file or directory

On my Fedora 20 system I use scp a lot, and this is the second time I encounter this, when I run this command: scp -r -P PORT user@host:/home/user/something/{file1,folder1,folder2,folder3,folder4} ...
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4answers
11k views

What command should I run after making changes to /etc/passwd file

I have made some changes to /etc/passwd file ,now I wanted to see if the effect of changes taken place or not .What command should I run for that. For example after making change to ...
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3answers
988 views

Securely feeding a program with a password

After understanding the problem with using a password in the command line, I need to find a way of feeding a program with a password without it being a problem (without the password being recorded ...
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3answers
300 views

Automatic login via ssh (no GUI environment installed / no ssh-agent available)?

I have three systems, and I want to have them doing backups between them periodically. The two of them, have Debian Wheezy installed and the other one has Ubuntu 12.04 installed. Only the Ubuntu has a ...
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2answers
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How to remove root password on Debian?

I'm running Debian in a virtual machine and for convenience I would like to remove the password on root (since it doesn't really matter what happens to this box). Internet hasn't been too helpful on ...
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327 views

Trying to crack a weak password using John

I have a computer from the 1990s. It has an (extent) EFS file-system which cannot be wrote to in linux, so i cannot reset the password manually. So i have to crack my password. For this I am trying to ...
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2answers
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/etc/shadow date of last password change—UTC or local time?

man 5 shadow gives the following description of the third field in each line: The date of the last password change, expressed as the number of days since Jan 1, 1970. The value 0 has a ...
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2answers
238 views

Why rejection of password is much slower than acceptance of it? [duplicate]

In both my Linux and OSX machines when I type in the password to login, a correct password is accepted immediately. However, if I type a wrong password, checking process takes much longer. How is ...
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4answers
410 views

Login into a GNU/Linux distribution is taking too long

So, When I try to login with my username and password (in tty), and insert a wrong password, I need to wait around 5 seconds for the system to tell me that the password is wrong. Why the validating ...
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3answers
491 views

Something like pwgen-win for linux?

Is there some kind of pwd generator for Linux that has a nice GUI and options like this one for Windows? I know that there is pwgen, but as far as I know it does not support mouse/keyboard entropy and ...
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2answers
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Why should you NEVER edit the /etc/shadow file directly?

In another answer here on UNIX & Linux Stack Exchange Michael D Parker wrote, in response to someone saying that doing so was "safe", that:Usually you should NEVER edit the /etc/shadow file ...
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4answers
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Kali Linux: On install, designated root password cannot login - incorrect password

I found an old laptop lying around and I figured I would install Kali Linux on it to learn more about penetration testing and to try to break into my servers for practice and learning more about ...
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2answers
265 views

Determining the Password Status of a User

I have a debian box that I connect to via SSH. I have removed the password from the users root, and my personal account using the instructions here, and set up a public/private key pair so I can log ...
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2answers
427 views

User created without a password behaves as if he had one

Inside one of my scripts, I created an user based on a directory arrangement on another machine. The thing is that this user, created without a password, behaves just as he had one : he has sudo ...
4
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1answer
20k views

How to set password for users in AIX using single line command?

Is there any way in which I can set the password for a newly created user account in AIX in a one line command? I don't want to give any prompt to the user. If there is a command, it should set the ...
4
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1answer
514 views

Encrypt word X to /etc/shadow encryption

I've changed my password to X and the shadow file has changed to: ahmad:$1$oYINSKjP$eCkCtJV/2dXerAD57WQPj/:15425:0:99999:7::: I see the encrypted X as $1$oYINSKjP$eCkCtJV/2dXerAD57WQPj/. How can I ...
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2answers
439 views

Password protecting a system file? (e.g. /etc/resolv.conf)

I am trying to parental control myself by restricting web access via OpenDNS. The OpenDNS account password will be handed to someone trustworthy. Now, I want to put some restriction on the ...
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1answer
20k views

How to create a user with given password on SuSE from command line?

I need to create bunch of new users with given password. What I want is a script that I would pass the user name of new user and it will create/add the user and set its password. (the password is the ...
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3answers
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scp: localhost password not accepted

I'm attempting to copy a public key to a remote server. I'm logged in locally as [localname] and the key resides locally at ~/.ssh/. I'm also ssh'd into [remote.com] as [remotename], and attempting to ...
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1answer
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Why 'mkpasswd -m sha-512' produce different result every time it is called?

I am using this function to create a password in the shadow file $ mkpasswd -m sha-512 password $6$o50n4EfNOBzfs$K5l5AcOI5e0I9n2df0LmR11OLSPKSVM6AGBOnWVfDDfMubb46MrAj0zehdLNEoYzD2fj5q4XUdDwexj/dWLHy/ ...
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2answers
11k views

Avoid “Authentication token manipulation error” on password change

I'm implementing a security policy that will force the users to introduce stricter passwords when they change their own: The /etc/pam.d/passwd configuration file is: #%PAM-1.0 auth include ...
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3answers
307 views

Randomise or shred memory of an application

Is it possible to randomise or shred memory of a particular application just after its life ends, or better, whenever it deallocates some memory? A command-line utility like this would be perfect: ...
4
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1answer
182 views

How to achieve conditional PAM authentication?

I am currently using auth required pam_unix.so try_first_pass nullok auth optional pam_ssh.so use_first_pass (plus some other, probably irrelevant entries Arch Linux added by default), which means ...
4
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1answer
66 views

Is it possible to add a password to moving or copying specific files on Linux?

I have a directory setup very nicely(i.e organized with READMEs and easy navigation etc.). I would like people to be able to access the files in this directory maybe even copy them to their own ...
4
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1answer
261 views

Change the root password of a Linux image

I'm building a jessie build of Debian. Passwords are saved in /etc/shadow in the build tree, but they are salted obviously so I cannot change it just by editing the file. If this was my installed ...
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2answers
244 views

SSH password requested when in Tmux

When I connect to my remote machine I do authenticate using a rsa key (I think is rsa, don't remember). If I do ssh from a regular shell I get logged on the machine without a password. However if I ...
4
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1answer
457 views

Export passwords from the `pass` password manager

I've been using the pass password manager for a year or so now, and it's awesome, but sometimes I like to test other password managers and then I need my passwords back. So far I've just been adding ...
4
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1answer
125 views

Self-contained password manager with CLI [closed]

I'm looking for a password manager that has the following properties: The manager is entirely self-contained. I take and install a directory on a thumbdrive and execute from that drive. It should ...
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2answers
4k views

Debian Log In Failure With Correct Password

So I have a Debian distro at home (considering getting ubuntu), and I can't login. When I use the correct password is does this thing where it makes it look like it's going to login, and then it ...